I REFER to Mr C. G. Staddon's letter headlined, ''Off target'' (South China Morning Post, February 9). Mr Staddon claimed that on January 3, his wife and two children entered the immigration departure hall at 12.10 pm and took approximately 75 minutes to complete immigration clearance whereby the departure time of their plane QF78 was delayed. However, our computer records revealed that the party completed departure clearance at 1.12pm and QF78 took off at 1.47pm due to heavy air traffic rather than immigration delay. As a matter of fact, January 3 was the busiest day after the New Year holiday and about 36,000 passengers departed Hong Kong on that day. We have a system to check and record at 15 minutes intervals the passenger waiting time to monitor our performance in immigration clearance. Despite the lengthy waiting time as claimed by Mr Staddon, our records showed that the average number of passengers awaiting clearance at the departure hall ranged from 26 to 30 at each counter between 12 noon and 1pm. Taking our average passenger, it appears that we were able to achieve our performance target of clearing the passengers within the 30-minute waiting time. Therefore we were not ''Off target'' as so alleged by Mr Staddon. LANDIS TSE for Director of Immigration Immigration Department